I'm joining the conversation late. The Model "B" in my humble opinion is one of the best ever built for the purpose it is used ON.Everything everyone has advised you is good advice. The "B" can be a little touchy and usually lets you know when it's not happy with it's lowly position in carburetordom but, if you look at its history it has been used in everything from airplanes to boats and everything in between (forgive the soapbox boasting). A good way to check for leaks is to wave acetylene gas around every vacuum spot on motor.If the engine rev's up there is your leak. In a pinch you can use map gas in a propane torch. Now lets me ask you has the "B" been rebuilt by you or anyone? If so let me know and we will start from there. DOC.
